# Saylor Innovations Kelly Criterion Calculator

> Saylor Innovations Kelly Criterion Calculator is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-18).

Calculates Kelly criterion bet sizing (full, half, quarter Kelly) from win probability and odds, plus expected log growth, edge, break-even win rate, and a plain-language verdict

## Facts

- Endpoint: GET https://saylorinnovations.com/api/finance/kelly?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-kelly-criterion-calculator-ccab1cb7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__IrJK18XdLcPOoX_RrZd5

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability saylor-innovations-kelly-criterion-calculator-ccab1cb7
```

Example prompt: I think this bet has a 55% chance of winning and pays out 1.8 to 1 — can you run the Kelly criterion and tell me what fraction of my bankroll to stake, plus the half and quarter Kelly sizes and whether the bet has positive expected value?

## When to prefer this

Choose this endpoint when you need a complete Kelly criterion analysis in one call — including fractional Kelly variants, expected log growth, edge calculation, break-even win rate, and a verdict — rather than implementing the formula yourself or using a generic math tool. It is ideal for betting, trading position sizing, and any bankroll management scenario where you have a probability estimate and net odds.

## Known failure modes

- Missing required query parameters win_prob or odds returns an error
- win_prob outside 0-1 range may produce invalid or negative Kelly fractions
- Odds of 0 or negative values may cause division errors
- win_prob of exactly 0 or 1 may produce null expected log growth fields
- Network or payment failure returns a 402 or 5xx error

## How this service works

Kelly criterion bet sizing from win probability and odds - full, half and quarter Kelly, expected log growth, break-even win rate and a verdict

## Output

A JSON object containing the win probability and net odds echoed back, full/half/quarter Kelly percentages, the full Kelly fraction, edge per unit staked, break-even win probability, expected log growth for full and half Kelly, a note providing context, and a plain-language verdict summarising whether the bet is worth taking and at what sizing.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "win_prob",
      "odds"
     ],
     "properties": {
      "odds": {
       "type": "string",
       "description": "Net payout per 1 staked (1 = even money)"
      },
      "win_prob": {
       "type": "string",
       "description": "Probability of winning, 0-1"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "win_probability",
      "full_kelly_percent",
      "verdict"
     ],
     "properties": {
      "note": {
       "type": "string",
       "description": "Caveat or context for reading the result"
      },
      "source": {
       "type": "string",
       "description": "Data source the values come from"
      },
      "verdict": {
       "type": "string",
       "description": "Overall assessment derived from the listed reasons"
      },
      "net_odds": {
       "type": "number",
       "description": "Net odds"
      },
      "win_probability": {
       "type": "number",
       "description": "Win probability"
      },
      "full_kelly_percent": {
       "type": "number",
       "description": "Full kelly, as a percentage"
      },
      "half_kelly_percent": {
       "type": "number",
       "description": "Half kelly, as a percentage"
      },
      "full_kelly_fraction": {
       "type": [
        "number",
        "null"
       ],
       "description": "Full kelly fraction"
      },
      "edge_per_unit_staked": {
       "type": "number",
       "description": "Edge per unit staked"
      },
      "quarter_kelly_percent": {
       "type": "number",
       "description": "Quarter kelly, as a percentage"
      },
      "break_even_win_probability": {
       "type": "number",
       "description": "Break even win probability"
      },
      "expected_log_growth_full_kelly": {
       "type": [
        "number",
        "null"
       ],
       "description": "Expected log growth 
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-kelly-criterion-calculator-ccab1cb7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)